Figure out the meaning of the timestamp_msec param in some APIs

[quietlynn]

I was trying to sniff for the API for adding comments. However, I can't get the timestamp_msec param right. It looks like a timestamp, but it differs from the current datetime. Google+ rejected all my requests with HTTP 400.

I tried to take a look at the compiled javascript, but I failed.

[tzafrir]

On my system, when posting a comment timestamp_msec is exactly the current time in milliseconds - equal to new Date().getTime()